1. Field
Example embodiments relate to a power supply. Other example embodiments relate to a power supply and a display apparatus, which has the power supply, designed to improve operational efficiency.
2. Description of Related Art
A variety of displays, such as plasma display panels (PDPs), liquid crystal displays (LCDs) and light emitting diode (LED) displays, have recently been developed and distributed. Among them, LED displays are more widely used due to their use of a stable and highly-efficient direct current (DC) power supply, generation of relatively little heat, and relatively low consumption of power. LEDs are devices that emit light when voltage is applied (to opposite terminals). To allow the light emitted from such an LED to maintain constant brightness, a constant voltage is stably applied to the opposite terminals of the LED. Thus, LED displays may be equipped with a switching mode power supply (SMPS), which supplies constant voltage.
A SMPS is a power supply that receives input voltage, raises or lowers the input voltage according to the switching time of an internal switching element, and generates an output voltage having a desired level. The SMPS is capable of being manufactured in a relatively small-size and light-weight, and thus is widely used. Here, an operating time of the switching element is controlled by the duty ratio of a switching signal input into the switching element. The SMPS continuously monitors a change in level of the output voltage to vary the duty ratio of the switching signal depending on the level change of the output voltage, thereby controlling the output voltage at a relatively constant level.